Synthetic Chemistry of Cyclopropenone Acetals. Penitricin and Buckminsterfullerene.

Abstract

A variety of substituted cyclopropenone acetals have been prepared and studied for the purpose of gaining further insights into their organometallic and thermal chemistry. Acidic hydrolysis of the acetals gave the corresponding cyclopropenones, among these are a naturally occurring cyclopropenone antibiotic, penitricin. A new class of cysteine protease inhibitor can be realized if the penitricin moiety is contrived as a dipeptide-like binding site. Thermolysisbf substituted cyclopropenone acetals generates vinyl carbene species that undergo [1 + 2] and [3 + 2] cycloadditions to electrondeficient olefins. The cyclopropenone acetal also serves as a precursor to a dipolar trimethylenemethane. The vinyl carbene and the trimethylenemethane species undergo cycloaddition to give buckminsterfullerenes, with which the various organic derivatives of fullerenes generated have been shown to exhibit photo-induced cytotoxicity, DNA cutting activity and enzyme inhibition.